The Center for Biological Diversity (CBD) today filed notice of intent to sue the U. S. Fish and Wildlife Service (USFWS) for failing to take emergency action to protect the extremely endangered Miami blue butterfly (Hemiargus thomasi bethunebakeri) under the Endangered Species Act (ESA). The Miami blue butterfly is one of the rarest insects in North America, with only one viable population remaining in the wild in the lower Florida Keys. The USFWS invoked a controversial loophole in the ESA, making a determination in May 2005 that the Miami blue butterfly warrants listing as an endangered species, but that formal protection is “precluded” by higher priorities.

The Miami blue is a coastal butterfly that inhabits sunny areas at the edges of tropical hardwood forests in southern Florida. The species warrants immediate emergency listing because the population and habitat of this unique butterfly is disappearing at an alarmingly fast pace. Although the Miami blue butterfly could once be found as far north along the Florida coasts to about St. Petersburg and Daytona, it is now restricted to one isolated population at Bahia Honda Key State Park, estimated to be only 45-50 adults. Two major threats to the species are habitat loss and fragmentation of habitat. Much of the butterfly’s habitat range is the heavily urbanized south Florida coast. Other threats include pesticide application for mosquito control and the potential for unethical butterfly collection.

CBD Policy Director Kieran Suckling called the USFWS decision “callous and illegal,” noting that the butterfly could go extinct while awaiting federal protective regulations. Suckling characterized the warranted but precluded designation as a “regulatory purgatory” for endangered species, noting the average length of time a species remains on the list before receiving ESA protection is about 17 years.

The USFWS received a petition to list the Miami blue butterfly under the ESA on June 15, 2000 and made a 90-day finding that “listing this species may be warranted.” Under the ESA, the USFWS was required to issue a listing determination by June 15, 2001, but failed to meet this deadline. The USFWS proposed emergency listing of the species several times between November 2000 and December 2004, in recognition of significant population decline and increasing harm from known threats. However, senior USFWS officials in Washington declined to issue an emergency listing because of an existing captive-bred Miami blue butterfly population, despite the fact that the inclusion of a captive-bred butterflies could result in inaccurate population numbers and the loss of the species in the wild. The USFWS recently acknowledged that reintroductions from captive breeding has not been successful, since Miami blue butterflies have not become established at any release sites. The state of Florida emergency listed the Miami blue butterfly as a state endangered species in December of 2002.

The USFWS instead listed the Miami blue butterfly as a federal candidate species in May 2005, stating that ESA listing was “warranted but precluded.” Federal courts have repeatedly ruled that the USFWS has illegally placed gravely imperiled species on the warranted but precluded list as a delay tactic to avoid ESA protection, and has overturned such determinations for the Canada lynx and bull trout.

The ESA allows the USFWS to make a warranted but precluded determination only if it can demonstrate that it is making “expeditious progress” in listing higher priority species. However, every species listed under the Bush administration has been as a result of a citizen listing petition, lawsuit, or settlement agreement. The USFWS has attempted to blame litigation and court orders to designate critical habitat as an excuse for delaying listing of vanishing species. This is a ruse, as the ESA clearly allows use of the warranted but precluded list only when other species listings are being made rapidly. It is patently false for the Bush administration, which has consistently fought against increasing the ESA listing budget and is purposely starving the endangered species listing program, to claim insufficient resources to list the Miami blue butterfly.

The Center for Biological Diversity is a nonprofit environmental organization dedicated to the protection of native species and their habitats in the Western Hemisphere through science, education, policy, and environmental law. Using the citizen listing provision of the Endangered Species Act, listing petition and litigation efforts by the Center have led to federal protection of 119 threatened and endangered species and the conservation of more than 37 million acres of terrestrial habitats and nearly 4,500 miles of stream and aquatic habitats.